Qubit reset from excited states

ABSTRACT

Techniques regarding resetting highly excited qubits are provided. For example, one or more embodiments described herein can comprise a system, which can comprise a memory that can store computer executable components. The system can also comprise a processor, operably coupled to the memory, and that can execute the computer executable components stored in the memory. The computer executable components can comprise a reset component that can de-excite a qubit system to a target state by transitioning a population of a first excited state of the qubit system to a ground state and by applying a signal to the qubit system that transitions a population of a second excited state to the first excited state.

BACKGROUND

The subject disclosure relates to resetting qubits from excited states,and more specifically, to conditionally or unconditionally resettingqubits from excited states that can include states higher than a firstexcited energy level.

Quantum computers can encode information in one or more quantum bits(“qubits”) via quantized excitations of a degree of freedom insuperconducting devices. Qubits are prepared in a known state ofexcitation before circuits can be applied to them. Also, in somearchitectures qubits can be recycled throughout a quantum computation. Aprocess by which qubits are initialized to a known state with highfidelity can be referred to as a “reset” of the qubits.

Qubits can be reset to the known state, for example a ground state, viapassive or active preparation. For instance, a qubit reset can bepassively achieved by waiting a sufficient amount of time after the lastcircuit of the quantum computer has run in order for the energyrelaxation to return the qubit from its excited state to the targetstate (e.g., a ground state). To maintain high fidelity, it istraditionally necessary to consider various decay time constants;thereby limiting the throughput of the quantum computer. In anotherinstance, a qubit reset can be actively achieved applying one or moresignals to de-excite the qubit. Further, an active reset can beconditional, wherein the state of the qubit is initially interrogated,or unconditional, wherein the reset is initiated without interrogatingthe current state of the qubit.

A narrow range of qubit excited states is generally desired for quantumcomputations (e.g., a ground state and a first energy state). However,there is a finite probability that during operation qubits canunintentionally transition to higher excited states (e.g., a secondenergy state, a third energy state, etc.); thereby causing an error onthe circuit. If the qubit does not return to the ground state before thenext circuit is started, the next circuit will then be affected by theerror from the previous circuit rather than the desired result of beingindependent. Additionally, some circuits can intentionally transitionthe qubit to a higher level state, which will need to be returned to theground state before the next circuit can be run. Traditional resetprocedures are unable to efficiently and/or effectively reset a qubitregardless of the qubit's excited state; particularly when the qubit isbeing reset from one or more higher excited states. Further, someoperations, such as the measurement of transmons, can excite the qubitto the higher excited states.

SUMMARY

The following presents a summary to provide a basic understanding of oneor more embodiments of the invention. This summary is not intended toidentify key or critical elements, or delineate any scope of theparticular embodiments or any scope of the claims. Its sole purpose isto present concepts in a simplified form as a prelude to the moredetailed description that is presented later. In one or more embodimentsdescribed herein, systems, computer-implemented methods, apparatusesand/or computer program products that can reset a qubit from one or morehigh excited states are described

According to an embodiment, a system is provided. The system cancomprise a memory that stores computer executable components. The systemcan also comprise a processor, operably coupled to the memory, and thatcan execute the computer executable components stored in the memory. Thecomputer executable components can comprise a reset component that cande-excites a qubit system to a target state by transitioning apopulation of a first excited state of the qubit system to a groundstate, and by applying a signal to the qubit system that transitions apopulation of a second excited state to the first excited state. Anadvantage of such a system can be the unconditional reset of highlyexcited qubits.

In some examples, the system can comprise a transition component thatcan generate the signal that transitions the population of the secondexcited state to the first excited state. The signal can comprise atleast one transition signal selected from the group consisting of a pipulse transition signal and a microwave chirp transmission signal. Anadvantage of such a system can be the active and rapid transitioning ofqubit states.

According to an embodiment, a computer-implemented method is provided.The computer-implemented method can comprise transitioning, by a systemoperatively coupled to a processor, a population of a first excitedstate of a qubit system to a ground state. The computer-implementedmethod can also comprise applying, by the system, a signal to the qubitsystem that transitions a population of a second excited state to thefirst excited state. An advantage of such a computer-implemented methodcan be the reset of highly excited qubits without requiring a tunablelow frequency resonator.

In some examples, the transitioning the population of the first excitedstate to the ground state is performed via a reset selected from thegroup consisting of a measurement based reset, a sideband based reset, alow-Q reset, and a pi pulse reset. An advantage of such acomputer-implemented method can be the enablement of rapid qubit resetsbetween executing circuits of a quantum computer 108.

According to an embodiment, a computer program product for de-exciting aqubit system is provided. The computer program product can comprise acomputer readable storage medium having program instructions embodiedtherewith. The program instructions can be executable by a processor tocause the processor to transition, by the processor, a population of afirst excited state of the qubit system to a ground state. Also, theprogram instructions can cause the processor to apply, by the processor,a signal to the qubit system that transitions a population of a secondexcited state to the first excited state. An advantage of such acomputer program product can be the operation of quantum computers withlow error rates, even if the quantum circuit experiences energy leaksinto highly excited qubit states.

In some examples, the program instructions can further cause theprocessor to transition the population of the first excited state to theground state via a low-Q reset, and render, by the processor, a low-Qresonator of the qubit system to degenerate with the second excitedstate. An advantage of such a computer program product can be theunconditional reset of highly excited state qubits with minimal timebetween quantum circuit runs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram of an example, non-limiting systemthat can facilitate one or more conditional and/or unconditional qubitresets in accordance with one or more embodiments described herein.

FIG. 2 illustrates a block diagram of an example, non-limiting systemthat can facilitate one or more conditional and/or unconditional qubitresets in accordance with one or more embodiments described herein.

FIG. 3 illustrates a diagram of example, non-limiting bar graphs thatcan depict qubit populations in various excited states during a firststage of a qubit reset in accordance with one or more embodimentsdescribed herein.

FIGS. 4A-4C illustrate a diagram of example, non-limiting bar graphsthat can depict qubit populations in various excited states during aseries of pi-pulse de-excitations of qubit reset in accordance with oneor more embodiments described herein.

FIG. 5 illustrates a diagram of example, non-limiting bar graphs thatcan depict the qubit population in various excited states during amicrowave signal chirp of a qubit reset in accordance with one or moreembodiments described herein.

FIG. 6 illustrates a diagram of example, non-limiting bar graphs thatcan depict qubit populations in various excited states during a firststage of a low-Q qubit reset in accordance with one or more embodimentsdescribed herein.

FIG. 7 illustrates a diagram of example, non-limiting bar graphs thatcan depict the qubit population in various excited states during amicrowave signal chirp of a qubit reset in accordance with one or moreembodiments described herein.

FIG. 8 illustrates a flow diagram of an example, non-limitingcomputer-implemented method that can facilitate resetting one or morequbits in accordance with one or more embodiments described herein.

FIG. 9 illustrates a flow diagram of an example, non-limitingcomputer-implemented method that can facilitate resetting one or morequbits in accordance with one or more embodiments described herein.

FIG. 10 depicts a cloud computing environment in accordance with one ormore embodiments described herein.

FIG. 11 depicts abstraction model layers in accordance with one or moreembodiments described herein

FIG. 12 illustrates a block diagram of an example, non-limitingoperating environment in which one or more embodiments described hereincan be facilitated.

DETAILED DESCRIPTION

The following detailed description is merely illustrative and is notintended to limit embodiments and/or application or uses of embodiments.Furthermore, there is no intention to be bound by any expressed orimplied information presented in the preceding Background or Summarysections, or in the Detailed Description section.

One or more embodiments are now described with reference to thedrawings, wherein like referenced numerals are used to refer to likeelements throughout. In the following description, for purposes ofexplanation, numerous specific details are set forth in order to providea more thorough understanding of the one or more embodiments. It isevident, however, in various cases, that the one or more embodiments canbe practiced without these specific details.

Given the problems with other implementations of qubit resets; thepresent disclosure can be implemented to produce a solution to one ormore of these problems by enabling a qubit reset regardless of a qubit'sexcited state. Advantageously, one or more embodiments described hereincan be performed unconditionally. Further, various embodiments describedherein can enable higher throughput on quantum computing systems whileminimizing a negative impact on qubit fidelity. In addition, one or moreembodiments described herein can be performed without the necessity offlux-tunable elements; thereby, enabling use without modification to thequantum computer hardware.

Various embodiments of the present invention can be directed to computerprocessing systems, computer-implemented methods, apparatus and/orcomputer program products that facilitate the efficient, effective, andautonomous (e.g., without direct human guidance) conditional and/orunconditional qubit resets from highly excited energy states. Forexample, one or more embodiments described herein can regard anon-unitary operation to remove entropy from one or more qubits followedby a unitary operation that can remove a photon from one or moreremaining excited qubits. For instance, one or more qubit resetsdescribed herein can implement a microwave chirp signal to sweep acrossof variety of qubit excited state frequencies to promote de-excitation.Additionally, one or more qubit resets described herein can include aseries of pi-pulse signals that can transition a population of excitedqubits between excitation states to promote de-excitation.

The computer processing systems, computer-implemented methods, apparatusand/or computer program products employ hardware and/or software tosolve problems that are highly technical in nature (e.g., condition orunconditional qubit resets), that are not abstract and cannot beperformed as a set of mental acts by a human. For example, anindividual, or a plurality of individuals, cannot analyze qubit statesand/or derive signal frequencies with the efficiency needed to resetqubits between execution of quantum computer circuits.

Also, one or more embodiments described herein can constitute atechnical improvement over conventional qubit reset procedures byenabling an active qubit reset from high excitation states, such asenergy states greater than a second energy state (e.g., with referenceto a ground state). Additionally, various embodiments described hereincan demonstrate a technical improvement over conventional qubit resetprocedures by actively de-exciting highly excited qubits unconditionallywithout requiring the quantum computer to comprise custom flux-tunableelements. For example, various embodiments described herein canimplement a microwave chirp and/or a series of pi-pulse signals toremove photons from one or more qubits, and thereby perform anunconditional qubit reset.

Further, one or more embodiments described herein can have a practicalapplication by actively implementing a qubit reset of highly excitedqubits between circuit executions and/or circuit initializations. Forinstance, various embodiments described herein can be implemented forquantum computer error correction and/or to increase repetition rate inone or more quantum computers. One or more embodiments described hereincan actively control the excited state of one or more qubitsconditionally or unconditionally. Thereby, the one or more embodiments,can de-excite qubits with minimal time between circuit executions with alow error rate even if the qubits have leaked, intentionally orunintentionally, to highly excited states.

As described herein, the term “highly excited state” or “highly excitedstates” can refer to a qubit excitation state that has a greater energylevel than a first excitation state with reference to a groundexcitation state, which can be a qubit state having a minimal amount ofenergy. For example, the energy level of a qubit can be elevated fromthe ground state via excitation to a plurality of possible excitationstates. From the plurality of possible excitation states, the excitationstate having the lowest energy level can be the first excitation state.From the remaining plurality of possible excitation states, theexcitation state having the second to lowest energy level can be thesecond excitation state, wherein the pattern can continue to define athird excitation state, a fourth excitation state, etc. Thereby, higherexcitation states are association with higher energy levels. Excitationstates greater than the first excitation state (e.g., second excitationstate, third excitation state, etc.) can be referred to as highlyexcited states. As described herein, quantum computers can generally runusing qubits in the ground state or first excitation state; however,qubits can occasionally be excited to highly excited states duringoperation of the quantum computer (e.g., intentionally orunintentionally).

As described herein, the term “reset signal” can refer to one or moremicrowave signals generated by one or more microwave drives at afrequency that transitions a qubit population of a first excitationstate to a ground state. In various embodiments, the reset signal can beimplemented via a sideband reset, a measurement based reset, and/or alow-Q reset. For example, a sideband reset can include one or moremicrowave sideband reset techniques that deterministically drive one ormore qubits from a first energy state (e.g., first excitation state) toa second energy state (e.g., the ground state) without impacting otherenergy states (e.g., highly excited states). In another example, ameasurement based reset can include one or more techniques that measureif a qubit is in a first energy state (e.g., first excitation state) andthen applies a π-pulse to bring the qubit to a second energy state(e.g., the ground state) if needed. In a further example, one or morequbits can be coupled to a transmission line resonator having a lowquality factor and being degenerate with a defined state (e.g., firstexcitation state) such that one or more coupled qubits in the definedstate (e.g., first excitation state) de-excite via a rapid decay to alower state (e.g., ground state).

FIG. 1 illustrates a block diagram of an example, non-limiting system100 that can facilitate condition or unconditional qubit resets.Repetitive description of like elements employed in other embodimentsdescribed herein is omitted for sake of brevity. Aspects of systems(e.g., system 100 and the like), apparatuses or processes in variousembodiments of the present invention can constitute one or moremachine-executable components embodied within one or more machines,e.g., embodied in one or more computer readable mediums (or media)associated with one or more machines. Such components, when executed bythe one or more machines, e.g., computers, computing devices, virtualmachines, etc. can cause the machines to perform the operationsdescribed.

As shown in FIG. 1, the system 100 can comprise one or more servers 102,one or more networks 104, input devices 106, and/or quantum computers108. The server 102 can comprise reset component 110. The resetcomponent 110 can further comprise communications component 112 and/orground state component 114. Also, the server 102 can comprise orotherwise be associated with at least one memory 116. The server 102 canfurther comprise a system bus 118 that can couple to various componentssuch as, but not limited to, the reset component 110 and associatedcomponents, memory 116 and/or a processor 120. While a server 102 isillustrated in FIG. 1, in other embodiments, multiple devices of varioustypes can be associated with or comprise the features shown in FIG. 1.Further, the server 102 can communicate with one or more cloud computingenvironments.

The one or more networks 104 can comprise wired and wireless networks,including, but not limited to, a cellular network, a wide area network(WAN) (e.g., the Internet) or a local area network (LAN). For example,the server 102 can communicate with the one or more input devices 106and/or quantum computers 108 (and vice versa) using virtually anydesired wired or wireless technology including for example, but notlimited to: cellular, WAN, wireless fidelity (Wi-Fi), Wi-Max, WLAN,Bluetooth technology, a combination thereof, and/or the like. Further,although in the embodiment shown the reset component 110 can be providedon the one or more servers 102, it should be appreciated that thearchitecture of system 100 is not so limited. For example, the resetcomponent 110, or one or more components of reset component 110, can belocated at another computer device, such as another server device, aclient device, etc.

The one or more input devices 106 can comprise one or more computerizeddevices, which can include, but are not limited to: personal computers,desktop computers, laptop computers, cellular telephones (e.g., smartphones), computerized tablets (e.g., comprising a processor), smartwatches, keyboards, touch screens, mice, a combination thereof, and/orthe like. The one or more input devices 106 can be employed to command,augment, and/or modify one or more functions performed by the resetcomponent 110 into the system 100. For example, the one or more inputdevices 106 can send data to the communications component 112 (e.g., viaa direct connection and/or via the one or more networks 104).Additionally, the one or more input devices 106 can comprise one or moredisplays that can present one or more outputs generated by the system100 to a user. For example, the one or more displays can include, butare not limited to: cathode tube display (“CRT”), light-emitting diodedisplay (“LED”), electroluminescent display (“ELD”), plasma displaypanel (“PDP”), liquid crystal display (“LCD”), organic light-emittingdiode display (“OLED”), a combination thereof, and/or the like.

In various embodiments, the one or more input devices 106 and/or the oneor more networks 104 can be employed to input one or more settingsand/or commands into the system 100. For example, in the variousembodiments described herein, the one or more input devices 106 can beemployed to operate and/or manipulate the server 102 and/or associatecomponents. Additionally, the one or more input devices 106 can beemployed to display one or more outputs (e.g., displays, data,visualizations, and/or the like) generated by the server 102 and/orassociate components. Further, in one or more embodiments, the one ormore input devices 106 can be comprised within, and/or operably coupledto, a cloud computing environment.

In various embodiments, the one or more quantum computers 108 cancomprise quantum hardware devices that can utilize the laws of quantummechanics (e.g., such as superposition and/or quantum entanglement) tofacilitate computational processing (e.g., while satisfying theDiVincenzo criteria). In one or more embodiments, the one or morequantum computers 108 can comprise a quantum data plane, a controlprocessor plane, a control and measurement plane, and/or a qubittechnology.

In one or more embodiments, the quantum data plane can include one ormore quantum circuits comprising physical qubits, structures to securethe positioning of the qubits, and/or support circuitry. The supportcircuitry can, for example, facilitate measurement of the qubits' stateand/or perform gate operations on the qubits (e.g., for a gate-basedsystem). In some embodiments, the support circuitry can comprise awiring network that can enable multiple qubits to interact with eachother. Further, the wiring network can facilitate the transmission ofcontrol signals via a direct electrical connection and/orelectromagnetic radiation (e.g., optical, microwave, and/orlow-frequency signals). For instance, the support circuitry can compriseone or more superconducting resonators operatively coupled to the one ormore qubits. As described herein the term “superconducting” cancharacterize a material that exhibits superconducting properties at orbelow a superconducting critical temperature, such as aluminum (e.g.,superconducting critical temperature of 1.2 Kelvin) or niobium (e.g.,superconducting critical temperature of 9.3 Kelvin). Additionally, oneof ordinary skill in the art will recognize that other superconductormaterials (e.g., hydride superconductors, such as lithium/magnesiumhydride alloys) can be used in the various embodiments described herein.

In one or more embodiments, the control processor plane can identifyand/or trigger a Hamiltonian sequence of quantum gate operations and/ormeasurements, wherein the sequence executes a program (e.g., provided bya host processor, such as server 102) for implementing a quantumalgorithm. For example, the control processor plane can convert compiledcode to commands for the control and measurement plane. In one or moreembodiments, the control processor plane can further execute one or morequantum error correction algorithms.

In one or more embodiments, the control and measurement plane canconvert digital signals generated by the control processor plane, whichcan delineate quantum operations to be performed, into analog controlsignals to perform the operations on the one or more qubits in thequantum data plane. Also, the control and measurement plane can convertone or more analog measurement outputs of the qubits in the data planeto classical binary data that can be shared with other components of thesystem 100 (e.g., such as the reset component 110, via, for example, thecontrol processor plane). In one or more embodiments, the control andmeasurement plane can comprise one or more microwave drives that cangenerate microwave signals (e.g., microwave chirps and/or π-pulses) atvarious defined frequencies or frequency ranges.

One of ordinary skill in the art will recognize that a variety of qubittechnologies can provide the basis for the one or more qubits of the oneor more quantum computers 108. Two exemplary qubit technologies caninclude trapped ion qubits and/or superconducting qubits. For instance,wherein the quantum computer 108 utilizes trapped ion qubits, thequantum data plane can comprise a plurality of ions serving as qubitsand one or more traps that serve to hold the ions in specific locations.Further, the control and measurement plane can include: a laser ormicrowave source directed at one or more of the ions to affect the ion'squantum state, a laser to cool and/or enable measurement of the ions,and/or one or more photon detectors to measure the state of the ions. Inanother instance, superconducting qubits (e.g., such as superconductingquantum interference devices “SQUIDs”) can be lithographically definedelectronic circuits that can be cooled to milli-Kelvin temperatures toexhibit quantized energy levels (e.g., due to quantized states ofelectronic charge or magnetic flux). Superconducting qubits can beJosephson junction-based, such as transmon qubits and/or the like. Also,superconducting qubits can be compatible with microwave controlelectronics, and can be utilized with gate-based technology orintegrated cryogenic controls. Additional exemplary qubit technologiescan include, but are not limited to: photonic qubits, quantum dotqubits, gate-based neutral atom qubits, semiconductor qubits (e.g.,optically gated or electrically gated), topological qubits, acombination thereof, and/or the like. In various embodiments, the one ormore quantum computers 108 can include fixed-frequency superconductingqubits, which can undergo one or more reset procedures executed via thereset component 110.

In one or more embodiments, the communications component 112 canfacilitate the sharing of data between the reset component 110 and theone or more quantum computers 108, and/or vice versa (e.g., via a directelectrical connection and/or through the one or more networks 104).Additionally, the communications component 112 can facilitate thesharing of data between the reset component 110 and the one or moreinput devices 106, and/or vice versa (e.g., via a direct electricalconnection and/or through the one or more networks 104).

In various embodiments, the ground state component 114 can command theone or more quantum computer 108 to generate one or more reset signalsto transition a population of qubits from the first excitation state tothe ground state. For example, the one or more reset signals can beimplemented via sideband based reset, a measurement based reset, and/ora low-Q reset. In one or more embodiments, the one or more quantumcomputers 108 can generate the one or more reset signals via one or moremicrowave drives. Wherein the reset signal is implemented via one ormore measurement based resets, the energy level of the qubits comprisedwithin the one or more quantum computers 108 can be measured via readoutcircuitry also comprised within the one or more quantum computers 108(e.g., comprised within with the control and measurement plane). Forexample, the readout circuitry can share the measured excitation stateof the qubits with the ground state component 114 (e.g., via thecommunications component 112 and/or network 104), whereupon the groundstate component 114 can identify qubits in the first excitation statefor de-excitation by the reset signal.

In one or more embodiments, the ground state component 114 can executeone or more reset signals via the one or more quantum computers 108 toprepare the quantum computers 108 for one or more quantum computations.For instance, the ground state component 114 can execute the one or morereset signals prior to one or more quantum computations performed by theone or more quantum computers 108. In another instance, the ground statecomponent 114 can execute the one or more reset signals between quantumcomputations. Also, in various embodiments, the ground state component114 can execute the one or more reset signals unconditionally (e.g.,without ascertaining current energy state of the qubits).

FIG. 2 illustrates a diagram of the example, non-limiting system 100further comprising transition component 202 in accordance with one ormore embodiments described herein. Repetitive description of likeelements employed in other embodiments described herein is omitted forsake of brevity. In various embodiments, the transition component 202can execute one or more transition signals to transition qubitpopulations from one energy state to another. For instance, the one ormore transition signals can remove a photon from one or more excitedqubits to drive de-excitement.

In one or more embodiments, the one or more transition signals can beone or more microwave π-pulses that can be generated by one or moremicrowave drivers of the one or more quantum computers 108. For example,the one or more transition signals can comprise a π-pulse or a series ofπ-pulses driven at frequency that facilitates a transition between twodefined qubit energy states. For example, the one or more π-pulsetransition signals can transition a qubit population at first energystate (e.g., a first excitation state) with a qubit population at asecond energy state (e.g., a second excitation state) and vise versa.Thereby, the one or more π-pulse transition signals can exchange qubitpopulations between target energy states. The energy states subjected tothe exchange can be targeted by adjusting the frequency of the one ormore π-pulse transition signals. In various embodiments, the transitioncomponent 202 can set the frequency of the one or more π-pulsetransition signals, and thereby delineate the qubit energy statestargeted for transition.

In one or more embodiments, the one or more transition signals can beone or more microwave chirps that can be generated by one or moremicrowave drivers of the one or more quantum computers 108. For example,the one or more transition signals can comprise a microwave chirp thatsweeps across a range of frequencies. As the chirp transition signalsweeps the frequency range, the chirp transition signal can successivelyexchange qubit populations between energy states associated with thevarious frequencies within the frequency range. For instance, as thechirp transition signal is at a first frequency of the frequency range,the chirp transition signal can drive an exchange of a qubit populationbetween a first energy state and a second energy state. As the chirptransition signal progresses to a second frequency of the frequencyrange, the chirp transition signal can drive an exchange of a qubitpopulation between the second energy state and a third energy state. Asthe chirp transition signal further progresses to a third frequency ofthe frequency range, the chirp transition signal can further drive anexchange of a qubit population between the third energy state and afourth energy state. The chirp transition signal can continue to driveenergy state exchanges as the chirp transition signal progresses throughthe frequency range. Thereby, the chirp transition signal drive a seriesof energy state exchanges across a target range of energy statesassociated with the frequency range of the chirp transition signal. Invarious embodiments, the transition component 202 can set the frequencyrange of the one or more chirp transition signals, and thereby delineatethe qubit energy states targeted for sequential exchange.

In one or more embodiments, the one or more input devices 106 can beemployed to enter, populate, and/or modify one or more frequencyreference databases into the system 100. In various embodiments, the oneor more frequency reference databases can be stored in the one or morememories 116. The one or more frequency reference databases candelineate respective frequencies and qubit excitation state exchangesknown to be associated with the respective frequencies for the one ormore quantum computers 108. For example, the one or more frequencyreference databases can indicate the microwave frequency associated withone or more possible qubit excitation state exchanges for the one ormore quantum computers 108. For instance, the one or more frequencyreference database can include a first frequency value associated with aqubit exchange transition between the first and second excitationstates. In another instance, the one or more frequency referencedatabase can include a second frequency value associated with a qubitexchange transition between the second and third excitation states. Oneof ordinary skill in the art will recognize that the number of frequencyvalues included in the one or more frequency reference databases candepend on the number of possible excitation state exchanges for the oneor more quantum computers 108. Further, the frequency values can varydepending on the hardware characteristics of the quantum computers 108,wherein respective frequency reference tables can be associated withrespective quantum computers 108.

The reset component 110 (e.g., including the transition component 202)can analyze the one or more frequency reference databases to set thefrequencies for the one or more reset signals and/or π-pulse transitionsignals. For example, wherein the transition component 202 iscoordinating an excitation state exchange between the first excitationstate and the second excitation state, the transition component 202 canset the π-pulse transition signal to be executed by the one or morequantum computers 108 at a frequency associated with the first andsecond excitation state exchange within the one or more frequencyreference databases. Further, the reset component 110 (e.g., includingthe transition component 202) can analyze the one or more frequencyreference databases to set the frequency range for the one or more chirptransition signals. For example, wherein the transition component 202 iscoordinating a chirp transition signal to drive a sequence of excitationstate exchanges, the transition component 202 can set the chirptransition signal to be executed by the one or more quantum computers108 across a frequency range associated with the lowest and highestexcitation states of the qubit array. Additionally, in one or moreembodiments, the one or more input devices 106 can be employed to set adefault highest excitation state associated with the quantum computer108 being reset so as to facilitate unconditional performance. Forexample, wherein the default highest excitation state is set to thefourth excitation state, the reset component 110 can assume that atleast one qubit of the one or more quantum computers 108 populates thefourth excitation state and accordingly determine the number of resetsignal and/or transition signal repetitions to be implemented totransition the fourth excitation state qubit to the ground state.

In various embodiments, the transition component 202 can coordinate oneor more series of π-pulse transition signals to transition qubits ofhighly excited states to the first excitation state, whereupon theground state component 114 can initiate one or more reset signals tode-excite the qubits into the ground state. For example, the groundstate component 114 can first execute (e.g., via the one or more quantumcomputers 108) a reset signal that transitions qubits from the firstexcitation state to the ground state; thereby rendering a population offirst excitation state qubits equal to zero. Next, the transitioncomponent 202 can coordinate the series of π-pulse transition signals tosuccessively de-excite the remaining excited qubits. For instance, afirst π-pulse transition signal of the series can be generated at afrequency that exchanges qubits between the first excitation state andthe second excitation state. Since there are no qubits in the firstexcitation state (e.g., at least due to the reset signal), the exchangeresults in transitioning the second excitation state qubits to the firstexcitation state and rendering a population of second excitation statequbits equal to zero. Further, a second π-pulse transition signal of theseries can be generated at a frequency that exchanges qubits between thesecond excitation state and the third excitation state. Since there areno qubits in the second excitation state (e.g., at least due to thefirst π-pulse transition signal), the exchange results in transitioningthe third excitation state qubits to the second excitation state andrendering a population of third excitation state qubits equal to zero.The series of π-pulse transition signals can comprise any plurality ofπ-pulse transition signals, and thereby de-excite a correspondingplurality of qubits in highly excited states.

Subsequent to the transition component 202 implementing the series ofπ-pulse transition signals, the ground component 114 can implement asecond reset signal. The second reset signal can again render thepopulation of qubits in the first excitation state equal to zero, andthereby prepare the array of qubits for subjection to another series ofπ-pulse transition signals. The reset component 110 can repeatedlyimplement reset signals and series of π-pulse transition signals untilall the qubits of the one or more quantum computers 108 are in theground state. Further, reset component 110 can implement the resetsignals and/or π-pulse transition signals unconditionally; thereby,enabling an active and unconditional reset of qubits from highly excitedstates. FIGS. 3-4C can exemplify the reset process described above withregards to reset signals implemented by the ground state component 114and/or π-pulse transition signals implemented by the transitioncomponent 202.

In one or more embodiments, the reset component 110 can implement theπ-pulse transition signals and reset signals in one or more alternateorders. For example, to reset a qubit from the third excitation state,the reset component 110 can implement the described transition and/orreset signals in accordance with Sequence 1 or Sequence 2 below.

RS→Xp12→Xp23→RS→Xp12→RS  (1)

RS→Xp12→RS→Xp23→Xp12→RS  (2)

Wherein “RS” represents one or more reset signals, “Xp12” represents oneor more π-pulse transition signals having a frequency that can drive anexchange between the first and second excitation states, and “Xp23”represents one or more π-pulse transition signals having a frequencythat can drive an exchange between the second and third excitationstates. Further, one of ordinary skill in the art will recognize thatthe features of Sequence 1 or 2 can be extrapolated to regard otherexcitation states (e.g., greater than the third excitation state) inaccordance with the various embodiments described herein. For example,to reset a qubit from the fourth excitation state, the reset component110 can implement the described transition and/or reset signals inaccordance with Sequence 3 or Sequence 4 below.

RS→Xp12→Xp23→Xp34→RS→Xp12→Xp23→RS→Xp12→RS  (3)

RS→Xp12→RS→Xp23→Xp12→RS→Xp34→Xp23→Xp12→RS  (4)

Wherein “Xp34” represents one or more π-pulse transition signals havinga frequency that can drive an exchange between the third and fourthexcitation states.

In various embodiments, the transition component 202 can implement oneor more microwave chirp transition signals (e.g., via the one or morequantum computers 108) to transition qubits of highly excited states tothe first excitation state, whereupon the ground state component 114 caninitiate one or more reset signals to de-excite the qubits into theground state. For example, the ground state component 114 can firstexecute (e.g., via the one or more quantum computers 108) a reset signalthat transitions qubits from the first excitation state to the groundstate; thereby rendering a population of first excitation state qubitsequal to zero. Next, the transition component 202 can implement a chirptransition signal that de-excites the remaining excited qubits to oneenergy state lower than their current energy state. For instance, thechirp transition signal can drive a sequence of energy state exchangesas the chirp transition signal progresses through the target frequencyrange. As described above with regards to the series of π-pulses, sincethe first excitation state is empty at the time the chirp transitionsignal is implemented the sequential exchanges result in de-exciting theexcited qubits by one energy level (e.g., from the second excitationstate to the first excitation state, from the third excitation state tothe second excitation state, etc.).

Subsequent to the transition component 202 implementing the chirptransition signal, the ground component 114 can implement a second resetsignal. The second reset signal can again render the population ofqubits in the first excitation state equal to zero, and thereby preparethe array of qubits for subjection to another chirp transition signal.The reset component 110 can repeatedly implement reset signals and chirptransition signals until all the qubits of the one or more quantumcomputers 108 are in the ground state. Further, reset component 110 canimplement the reset signals and/or chirp transition signalsunconditionally; thereby, enabling an active and unconditional reset ofqubits from highly excited states. FIGS. 3 and 5 can exemplify the resetprocess described above with regards to reset signals implemented by theground state component 114 and/or chirp transition signals implementedby the transition component 202.

In various embodiments, the transition component 202 can implement oneor more π-pulse and/or microwave chirp transition signals (e.g., via theone or more quantum computers 108) to transition qubits to a targetenergy state, wherein the one or more qubits can be coupled to one ormore superconducting resonators having a low quality factor. Upontransitioning to the target energy state, the qubits can de-excite viadecay to facilitate a reset. The reset component 110 can repeatedlyimplement π-pulse and/or chirp transition signals until all the qubitsof the one or more quantum computers 108 are transitioned to the low-Qdecaying target energy state. Further, reset component 110 can implementthe one or more π-pulse and/or chirp transition signals unconditionally;thereby, enabling an active and unconditional reset of qubits fromhighly excited states. FIGS. 6-7 can exemplify the reset processdescribed above with regards to one or more π-pulse and/or chirptransition signals implemented by the transition component 202 inconjunction with a low-Q resonator (e.g., comprised within the one ormore quantum computers 108).

Coupling the one or more qubits to one or more superconductingresonators having a low quality factor can facilitate a reset of the oneor more qubits to the ground state or a desired excitation state. Forexample, in one or more embodiments the reset component 110 can resetthe one or more qubits to a desired excitation state from anywhere inthe qubit manifold. For instance, the low-Q resonator can be degeneratewith a target excitation state that is one excitation state higher thanthe desired excitation state, wherein repeated implementation of π-pulsetransition signals or chirp transition signals can coordinate transitionof the qubits to the desired excitation state. The one or more chirptransition signals and/or π-pulse transition signals can add a photon toqubits in states below the target excitation state and remove a photonfrom qubits above the target excitation state. Thereby, the resetcomponent 110 can transition the qubits into the target excitation statethrough repeatedly implementation of the one or more transition signals.Subsequently, the reset component 110 can transition the qubits fromtheir degenerative state to the desired excitation state through one ormore further implementations of the transition signals. Further,resetting the qubits to the desired excitation state can be performed bythe reset component 110 unconditionally.

For example, wherein the desired excitation state is the firstexcitation state and the qubit array comprises one or more qubits in atleast the third excitation state, the low-Q resonator can be degeneratewith respect to the second excitation state. The transition component202 can apply one or more chirp transition signals or π-pulse transitionsignals to transition any qubits in the first excitation state to thesecond excitation state, whereupon the qubits can decay back rapidly.Further, the transition component 202 can apply one or more chirptransition signals or π-pulse transition signals to transition the thirdexcitation state qubits to the second excitation state, whereupon thequbits can decay quickly. Repeated implementation of the chirp and/orπ-pulse transition signals can return all the qubits of the qubit arrayto the first excitation state.

FIG. 3 illustrates a diagram of example, non-limiting graphs that canexemplify the effects of one or more reset signals implemented by theground state component 114 in accordance with one or more embodimentsdescribed herein. Repetitive description of like elements employed inother embodiments described herein is omitted for sake of brevity. Asshown in FIG. 3, graphs 302 and/or 304 can depict the qubit populationassociated with a variety of excitation states for an exemplary qubitarray of the one or more quantum computers. For instance, the exemplaryqubit array comprises qubits in the ground state (e.g., excitation state0), the first excitation state (e.g., excitation state 1), the secondexcitation state (e.g., a highly excited state 2), the third excitationstate (e.g., a highly excited state 3), and the fourth excitation state(e.g., a highly excited state 4).

In various embodiments, the ground state component 114 can implement oneor more reset signals (e.g., via the one or more quantum computers 108)by a sideband reset and/or a measurement based reset. As shown in graph304, the one or more reset signals (e.g., indicated by “RS” in FIG. 3)can transition the qubit population initially in the first excitationstate to the ground state. Further, the one or more reset signals canleave the qubit populations of the highly excited states unaffected. Theground state component 114 can implement the one or more reset signalsto achieve a de-excitation exemplified by FIG. 3 to initialize one ormore qubit resets in accordance with one or more embodiments describedherein.

FIGS. 4A-4C illustrate diagrams of example, non-limiting graphs that canexemplify the effects of one or more π-pulse transition signalsimplemented by the transition component 202 in accordance with one ormore embodiments described herein. Repetitive description of likeelements employed in other embodiments described herein is omitted forsake of brevity. FIG. 4A exemplifies the effect that can be achieved viathe implementation of one or more π-pulse transition signals by thetransition component 202. As shown in FIG. 4A, the transition component202 can implement (e.g., via the one or more quantum computers 108) oneor more first π-pulse transition signals (e.g., indicated by “Xp12” inFIG. 4A) of a series of π-pulse transition signals to exchange qubitpopulations of the exemplary qubit array between the first excitationstate and the second excitation state. Since, one or more previouslyimplemented reset signals have emptied the qubit population in the firstexcitation state (e.g., as shown in graph 304), the first π-pulsetransition signal can effectively de-excite qubits from the secondexcitation state to the first excitation state (e.g., as shown in graph402).

As shown in FIG. 4B, the transition component 202 can further implement(e.g., via the one or more quantum computers 108) one or more secondπ-pulse transition signals (e.g., indicated by “Xp23” in FIG. 4B) of aseries of π-pulse transition signals to exchange qubit populations ofthe exemplary qubit array between the second excitation state and thethird excitation state. For example, the one or more second π-pulsetransition signals (e.g., indicated by “Xp23” in FIG. 4B) can have adifferent frequency than the one or more first π-pulse transitionsignals (e.g., indicated by “Xp12” in FIG. 4A). Since, the one or morefirst π-pulse transition signals have emptied the qubit population inthe second excitation state (e.g., as shown in graph 402), the secondπ-pulse transition signal can effectively de-excite qubits from thethird excitation state to the second excitation state (e.g., as shown ingraph 404).

As shown in FIG. 4C, the transition component 202 can further implement(e.g., via the one or more quantum computers 108) one or more thirdπ-pulse transition signals (e.g., indicated by “Xp34” in FIG. 4C) of aseries of π-pulse transition signals to exchange qubit populations ofthe exemplary qubit array between the third excitation state and thefourth excitation state. For example, the one or more third π-pulsetransition signals (e.g., indicated by “Xp34” in FIG. 4C) can have adifferent frequency than the one or more second π-pulse transitionsignals (e.g., indicated by “Xp23” in FIG. 4B). Since, the one or moresecond π-pulse transition signals have emptied the qubit population inthe third excitation state (e.g., as shown in graph 404), the thirdπ-pulse transition signal can effectively de-excite qubits from thefourth excitation state to the third excitation state (e.g., as shown ingraph 406).

Thereby, FIGS. 4A-4C can depict a series of π-pulse transition signalscomprising three π-pulse transition signals that can be implemented bythe transition component 202. As a result of the series of π-pulsetransition signals, all of the excited qubits can be de-excited by oneexcitation state and the qubit population of the fourth excitation statecan be rendered zero. In accordance with the various embodimentsdescribed herein, the ground state component 114 can subsequentlyimplement a second reset signal to de-excite the qubits of the firstexcitation state, and the transition component 202 can implement asecond series of π-pulse transition signals (e.g., comprising twoπ-pulse transition signals) to de-excite the remaining highly excitedstate qubits. The reset component 110 can repeat the implementations ofthe reset signals and/or 7C-pulse transition signals exemplified inFIGS. 3-4C until all the qubits of the exemplary qubit array arede-excited to the ground state. One of ordinary skill in the art willrecognize that the number of repetitions performed by the resetcomponent 110 can be based on the highest excitation state experiencedby the qubit array.

FIG. 5 illustrates a diagram of example, non-limiting graphs that canexemplify the effects of one or more chirp transition signalsimplemented by the transition component 202 in accordance with one ormore embodiments described herein. Repetitive description of likeelements employed in other embodiments described herein is omitted forsake of brevity. FIG. 5 exemplifies the effect that can be achieved viathe implementation of one or more chirp transition signals by thetransition component 202. As shown in FIG. 5, the one or more chirptransition signals can sequentially exchange qubits between increasinglyhigher excitation states so as to de-excite the excited qubits by oneexcitation state and de-populate the qubit population of the exemplaryqubit array's highest excitation state (e.g., de-populating the fourthexcitation state for the example qubit array associated with FIG. 5).

FIG. 6 illustrates a diagram of example, non-limiting graphs that canexemplify the effects of using one or more low-Q resonators to de-exciteone or more target excitation states in accordance with one or moreembodiments described herein. Repetitive description of like elementsemployed in other embodiments described herein is omitted for sake ofbrevity. As shown in FIG. 6, the example qubit array can be coupled toone or more low-Q resonators that can degenerate with, for example, thesecond excitation state. Graph 602 exemplifies that qubits entering thesecond excitation state can rapidly decay (e.g., to the first excitationstate).

FIG. 7 illustrates a diagram of example, non-limiting graphs that canexemplify the effects of using one or more low-Q resonators to de-exciteone or more target excitation states in accordance with one or moreembodiments described herein. Repetitive description of like elementsemployed in other embodiments described herein is omitted for sake ofbrevity. As shown in FIG. 7, one or more transition signals (e.g.,chirps and/or π-pulses) can be implemented to add a photon to theexcitation states that are below the excitation state degenerative withthe low-Q resonator (e.g., the second excitation state) and remove aphoton from the excitation states that are above the excitation statedegenerative with the low-Q resonator.

As shown in FIG. 7, the transition component 202 can implement one ormore chirp transition signals or series of π-pulse transition signals todrive a sequence of excitation state exchanges. Among the sequence ofexcitation state exchanges, qubits of the first excitation state cantransition to the second excitation state, and qubits of the groundstate can transition to the first excitation state. Further, the qubitsthat have transitioned to the second excitation state from the firstexcitation state can then decay to the first excitation state due to thelow-Q resonator (e.g., as shown in FIG. 6). Thereupon, the sequence ofexcitation state exchanges can continue such that the qubits of thethird excitation state can transition to the second excitation state,and the qubits of the fourth excitation state can transition to thethird excitation state. Moreover, the qubits that have transitioned tothe second excitation state from the third excitation state can thendecay to the first excitation state due to the low-Q resonator (e.g., asshown in FIG. 6).

In various embodiments, the transition component 202 can repeatedlyimplement transition signals (e.g., chirp transition signals and/orπ-pulse transition signals) to further transition highly excited statequbits to the second excitation state for decay (e.g., with regards tothe exemplary qubit array characterized by FIG. 7, transitioning thequbits remaining in the third excitation state to the second excitationstate). Once the qubits have de-excited due to rapid decay driven by thelow-Q resonator, the reset procedure can terminate (e.g., if thedegenerative state is the desired excitation state of the qubits), orthe reset procedure can continue in accordance with various embodimentsdescribed herein to de-excite the qubits to the ground state (e.g.,wherein the degenerative state is the first excitation state, as shownin FIGS. 6-7, one or more reset signals can be implemented to return thequbits to the ground state).

FIG. 8 illustrates a flow diagram of an example, non-limitingcomputer-implemented method 800 that can facilitate one or moreunconditional qubit resets in accordance with one or more embodimentsdescribed herein. Repetitive description of like elements employed inother embodiments described herein is omitted for sake of brevity.

At 802, the computer-implemented method 800 can comprise transitioning(e.g., via ground state component 114), by a system 100 operativelycoupled to a processor 120, a population of a first excited state of aqubit system to a ground state. For example, the transitioning at 802can comprise implementing one or more reset signals via one or morequantum computers 108 in accordance with various embodiments describedherein. For instance, the transitioning at 802 can implement one or morereset signals (e.g., via a sideband reset, measurement based reset,and/or coupling with a low-Q resonator) to transition one or more qubitsof one or more quantum computers 108 from a first excitation state to aground state.

At 804, the computer-implemented method 800 can comprise applying (e.g.,via transition component 202), by the system 100, one or more signals tothe qubit system that transitions a population of a second excited stateto the first excited state. For example, the signals applied at 804 canbe one or more transition signals (e.g., microwave chirps and/orπ-pulses) in accordance with various embodiments described herein. Forinstance, the signals at 804 can de-excite the population of the secondexcited state (e.g., one or more highly excited states, such as a secondexcitation state) to the first excited state (e.g., first excitationstate). As described herein, the one or more transition signals (e.g.,microwave chirps and/or π-pulses) can drive a sequence of excitationstate exchanges, and/or can be repeatedly applied until all of thehighly excited states are de-populated.

FIG. 9 illustrates a flow diagram of an example, non-limitingcomputer-implemented method 900 that can facilitate one or moreunconditional qubit resets in accordance with one or more embodimentsdescribed herein. Repetitive description of like elements employed inother embodiments described herein is omitted for sake of brevity.

At 902, the computer-implemented method 800 can comprise transitioning(e.g., via ground state component 114), by a system 100 operativelycoupled to a processor 120, a population of a first excited state of aqubit system to a ground state. For example, the transitioning at 902can comprise implementing one or more reset signals via one or morequantum computers 108 in accordance with various embodiments describedherein. For instance, the transitioning at 902 can implement one or morereset signals (e.g., via a sideband reset, measurement based reset,and/or coupling with a low-Q resonator) to transition one or more qubitsof one or more quantum computers 108 from a first excitation state to aground state.

At 904, the computer-implemented method 900 can comprise applying (e.g.,via transition component 202), by the system 100, one or more signals tothe qubit system that transitions a population of a second excited stateto the first excited state. For example, the signals applied at 804 canbe one or more transition signals (e.g., microwave chirps and/orπ-pulses) in accordance with various embodiments described herein. Forinstance, the signals at 804 can de-excite the population of the secondexcited state (e.g., one or more highly excited states, such as a secondexcitation state) to the first excited state (e.g., first excitationstate). As described herein, the one or more transition signals (e.g.,microwave chirps and/or π-pulses) can drive a sequence of excitationstate exchanges.

At 906, the computer-implemented method 900 can comprise transitioning(e.g., via ground state component 114), by a system 100 operativelycoupled to a processor 120, the population of a first excited state of aqubit system to the ground state. For example, the transitioning at 906can comprise implementing one or more second reset signals via one ormore quantum computers 108 in accordance with various embodimentsdescribed herein. As indicated at 908, the computer-implemented method900 can repeat steps 904 and 906 to de-excite highly excited statequbits to the first excitation state and implement one or more resetsignals. In various embodiment, the computer-implemented method 900 canrepeat steps 904 and 906 at 908 a defined number of times (e.g., one ormore input devices 106 can be employed to define the number ofrepetitions). Predefining the number of repetitions can facilitateunconditional execution of the computer-implemented method 900 (e.g.,without requiring a measurement assessment of state of the qubits).

It is to be understood that although this disclosure includes a detaileddescription on cloud computing, implementation of the teachings recitedherein are not limited to a cloud computing environment. Rather,embodiments of the present invention are capable of being implemented inconjunction with any other type of computing environment now known orlater developed.

Cloud computing is a model of service delivery for enabling convenient,on-demand network access to a shared pool of configurable computingresources (e.g., networks, network bandwidth, servers, processing,memory, storage, applications, virtual machines, and services) that canbe rapidly provisioned and released with minimal management effort orinteraction with a provider of the service. This cloud model may includeat least five characteristics, at least three service models, and atleast four deployment models.

Characteristics are as follows:

On-demand self-service: a cloud consumer can unilaterally provisioncomputing capabilities, such as server time and network storage, asneeded automatically without requiring human interaction with theservice's provider.

Broad network access: capabilities are available over a network andaccessed through standard mechanisms that promote use by heterogeneousthin or thick client platforms (e.g., mobile phones, laptops, and PDAs).

Resource pooling: the provider's computing resources are pooled to servemultiple consumers using a multi-tenant model, with different physicaland virtual resources dynamically assigned and reassigned according todemand. There is a sense of location independence in that the consumergenerally has no control or knowledge over the exact location of theprovided resources but may be able to specify location at a higher levelof abstraction (e.g., country, state, or datacenter).

Rapid elasticity: capabilities can be rapidly and elasticallyprovisioned, in some cases automatically, to quickly scale out andrapidly released to quickly scale in. To the consumer, the capabilitiesavailable for provisioning often appear to be unlimited and can bepurchased in any quantity at any time.

Measured service: cloud systems automatically control and optimizeresource use by leveraging a metering capability at some level ofabstraction appropriate to the type of service (e.g., storage,processing, bandwidth, and active user accounts). Resource usage can bemonitored, controlled, and reported, providing transparency for both theprovider and consumer of the utilized service.

Service Models are as follows:

Software as a Service (SaaS): the capability provided to the consumer isto use the provider's applications running on a cloud infrastructure.The applications are accessible from various client devices through athin client interface such as a web browser (e.g., web-based e-mail).The consumer does not manage or control the underlying cloudinfrastructure including network, servers, operating systems, storage,or even individual application capabilities, with the possible exceptionof limited user-specific application configuration settings.

Platform as a Service (PaaS): the capability provided to the consumer isto deploy onto the cloud infrastructure consumer-created or acquiredapplications created using programming languages and tools supported bythe provider. The consumer does not manage or control the underlyingcloud infrastructure including networks, servers, operating systems, orstorage, but has control over the deployed applications and possiblyapplication hosting environment configurations.

Infrastructure as a Service (IaaS): the capability provided to theconsumer is to provision processing, storage, networks, and otherfundamental computing resources where the consumer is able to deploy andrun arbitrary software, which can include operating systems andapplications. The consumer does not manage or control the underlyingcloud infrastructure but has control over operating systems, storage,deployed applications, and possibly limited control of select networkingcomponents (e.g., host firewalls).

Deployment Models are as follows:

Private cloud: the cloud infrastructure is operated solely for anorganization. It may be managed by the organization or a third party andmay exist on-premises or off-premises.

Community cloud: the cloud infrastructure is shared by severalorganizations and supports a specific community that has shared concerns(e.g., mission, security requirements, policy, and complianceconsiderations). It may be managed by the organizations or a third partyand may exist on-premises or off-premises.

Public cloud: the cloud infrastructure is made available to the generalpublic or a large industry group and is owned by an organization sellingcloud services.

Hybrid cloud: the cloud infrastructure is a composition of two or moreclouds (private, community, or public) that remain unique entities butare bound together by standardized or proprietary technology thatenables data and application portability (e.g., cloud bursting forload-balancing between clouds).

A cloud computing environment is service oriented with a focus onstatelessness, low coupling, modularity, and semantic interoperability.At the heart of cloud computing is an infrastructure that includes anetwork of interconnected nodes.

Referring now to FIG. 10, illustrative cloud computing environment 1000is depicted. As shown, cloud computing environment 1000 includes one ormore cloud computing nodes 1002 with which local computing devices usedby cloud consumers, such as, for example, personal digital assistant(PDA) or cellular telephone 1004, desktop computer 1006, laptop computer1008, and/or automobile computer system 1010 may communicate. Nodes 1002may communicate with one another. They may be grouped (not shown)physically or virtually, in one or more networks, such as Private,Community, Public, or Hybrid clouds as described hereinabove, or acombination thereof. This allows cloud computing environment 1000 tooffer infrastructure, platforms and/or software as services for which acloud consumer does not need to maintain resources on a local computingdevice. It is understood that the types of computing devices 1004-1010shown in FIG. 10 are intended to be illustrative only and that computingnodes 1002 and cloud computing environment 1000 can communicate with anytype of computerized device over any type of network and/or networkaddressable connection (e.g., using a web browser).

Referring now to FIG. 11, a set of functional abstraction layersprovided by cloud computing environment 1000 (FIG. 10) is shown.Repetitive description of like elements employed in other embodimentsdescribed herein is omitted for sake of brevity. It should be understoodin advance that the components, layers, and functions shown in FIG. 11are intended to be illustrative only and embodiments of the inventionare not limited thereto. As depicted, the following layers andcorresponding functions are provided.

Hardware and software layer 1102 includes hardware and softwarecomponents. Examples of hardware components include: mainframes 1104;RISC (Reduced Instruction Set Computer) architecture based servers 1106;servers 1108; blade servers 1110; storage devices 1112; and networks andnetworking components 1114. In some embodiments, software componentsinclude network application server software 1116 and database software1118.

Virtualization layer 1120 provides an abstraction layer from which thefollowing examples of virtual entities may be provided: virtual servers1122; virtual storage 1124; virtual networks 1126, including virtualprivate networks; virtual applications and operating systems 1128; andvirtual clients 1130.

In one example, management layer 1132 may provide the functionsdescribed below. Resource provisioning 1134 provides dynamic procurementof computing resources and other resources that are utilized to performtasks within the cloud computing environment. Metering and Pricing 1136provide cost tracking as resources are utilized within the cloudcomputing environment, and billing or invoicing for consumption of theseresources. In one example, these resources may include applicationsoftware licenses. Security provides identity verification for cloudconsumers and tasks, as well as protection for data and other resources.User portal 1138 provides access to the cloud computing environment forconsumers and system administrators. Service level management 1140provides cloud computing resource allocation and management such thatrequired service levels are met. Service Level Agreement (SLA) planningand fulfillment 1142 provide pre-arrangement for, and procurement of,cloud computing resources for which a future requirement is anticipatedin accordance with an SLA.

Workloads layer 1144 provides examples of functionality for which thecloud computing environment may be utilized. Examples of workloads andfunctions which may be provided from this layer include: mapping andnavigation 1146; software development and lifecycle management 1148;virtual classroom education delivery 1150; data analytics processing1152; transaction processing 1154; and qubit reset processing 1156.Various embodiments of the present invention can utilize the cloudcomputing environment described with reference to FIGS. 10 and 11 toperform one or more conditional or unconditional resets of highlyexcited state qubits in one or more quantum computers 108.

The present invention may be a system, a method, and/or a computerprogram product at any possible technical detail level of integration.The computer program product may include a computer readable storagemedium (or media) having computer readable program instructions thereonfor causing a processor to carry out aspects of the present invention.The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, configuration data for integrated circuitry, oreither source code or object code written in any combination of one ormore programming languages, including an object oriented programminglanguage such as Smalltalk, C++, or the like, and procedural programminglanguages, such as the “C” programming language or similar programminglanguages. The computer readable program instructions may executeentirely on the user's computer, partly on the user's computer, as astand-alone software package, partly on the user's computer and partlyon a remote computer or entirely on the remote computer or server. Inthe latter scenario, the remote computer may be connected to the user'scomputer through any type of network, including a local area network(LAN) or a wide area network (WAN), or the connection may be made to anexternal computer (for example, through the Internet using an InternetService Provider). In some embodiments, electronic circuitry including,for example, programmable logic circuitry, field-programmable gatearrays (FPGA), or programmable logic arrays (PLA) may execute thecomputer readable program instructions by utilizing state information ofthe computer readable program instructions to personalize the electroniccircuitry, in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the blocks may occur out of theorder noted in the Figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

In order to provide additional context for various embodiments describedherein, FIG. 12 and the following discussion are intended to provide ageneral description of a suitable computing environment 1200 in whichthe various embodiments of the embodiment described herein can beimplemented. While the embodiments have been described above in thegeneral context of computer-executable instructions that can run on oneor more computers, those skilled in the art will recognize that theembodiments can be also implemented in combination with other programmodules and/or as a combination of hardware and software.

Generally, program modules include routines, programs, components, datastructures, etc., that perform particular tasks or implement particularabstract data types. Moreover, those skilled in the art will appreciatethat the inventive methods can be practiced with other computer systemconfigurations, including single-processor or multiprocessor computersystems, minicomputers, mainframe computers, Internet of Things (“IoT”)devices, distributed computing systems, as well as personal computers,hand-held computing devices, microprocessor-based or programmableconsumer electronics, and the like, each of which can be operativelycoupled to one or more associated devices.

The illustrated embodiments of the embodiments herein can be alsopracticed in distributed computing environments where certain tasks areperformed by remote processing devices that are linked through acommunications network. In a distributed computing environment, programmodules can be located in both local and remote memory storage devices.For example, in one or more embodiments, computer executable componentscan be executed from memory that can include or be comprised of one ormore distributed memory units. As used herein, the term “memory” and“memory unit” are interchangeable. Further, one or more embodimentsdescribed herein can execute code of the computer executable componentsin a distributed manner, e.g., multiple processors combining or workingcooperatively to execute code from one or more distributed memory units.As used herein, the term “memory” can encompass a single memory ormemory unit at one location or multiple memories or memory units at oneor more locations.

Computing devices typically include a variety of media, which caninclude computer-readable storage media, machine-readable storage media,and/or communications media, which two terms are used herein differentlyfrom one another as follows. Computer-readable storage media ormachine-readable storage media can be any available storage media thatcan be accessed by the computer and includes both volatile andnonvolatile media, removable and non-removable media. By way of example,and not limitation, computer-readable storage media or machine-readablestorage media can be implemented in connection with any method ortechnology for storage of information such as computer-readable ormachine-readable instructions, program modules, structured data orunstructured data.

Computer-readable storage media can include, but are not limited to,random access memory (“RAM”), read only memory (“ROM”), electricallyerasable programmable read only memory (“EEPROM”), flash memory or othermemory technology, compact disk read only memory (“CD-ROM”), digitalversatile disk (“DVD”), Blu-ray disc (“BD”) or other optical diskstorage, magnetic cassettes, magnetic tape, magnetic disk storage orother magnetic storage devices, solid state drives or other solid statestorage devices, or other tangible and/or non-transitory media which canbe used to store desired information. In this regard, the terms“tangible” or “non-transitory” herein as applied to storage, memory orcomputer-readable media, are to be understood to exclude onlypropagating transitory signals per se as modifiers and do not relinquishrights to all standard storage, memory or computer-readable media thatare not only propagating transitory signals per se.

Computer-readable storage media can be accessed by one or more local orremote computing devices, e.g., via access requests, queries or otherdata retrieval protocols, for a variety of operations with respect tothe information stored by the medium.

Communications media typically embody computer-readable instructions,data structures, program modules or other structured or unstructureddata in a data signal such as a modulated data signal, e.g., a carrierwave or other transport mechanism, and includes any information deliveryor transport media. The term “modulated data signal” or signals refersto a signal that has one or more of its characteristics set or changedin such a manner as to encode information in one or more signals. By wayof example, and not limitation, communication media include wired media,such as a wired network or direct-wired connection, and wireless mediasuch as acoustic, RF, infrared and other wireless media.

With reference again to FIG. 12, the example environment 1200 forimplementing various embodiments of the aspects described hereinincludes a computer 1202, the computer 1202 including a processing unit1204, a system memory 1206 and a system bus 1208. The system bus 1208couples system components including, but not limited to, the systemmemory 1206 to the processing unit 1204. The processing unit 1204 can beany of various commercially available processors. Dual microprocessorsand other multi-processor architectures can also be employed as theprocessing unit 1204.

The system bus 1208 can be any of several types of bus structure thatcan further interconnect to a memory bus (with or without a memorycontroller), a peripheral bus, and a local bus using any of a variety ofcommercially available bus architectures. The system memory 1206includes ROM 1210 and RAM 1212. A basic input/output system (“BIOS”) canbe stored in a non-volatile memory such as ROM, erasable programmableread only memory (“EPROM”), EEPROM, which BIOS contains the basicroutines that help to transfer information between elements within thecomputer 1202, such as during startup. The RAM 1212 can also include ahigh-speed RAM such as static RAM for caching data.

The computer 1202 further includes an internal hard disk drive (“HDD”)1214 (e.g., EIDE, SATA), one or more external storage devices 1216(e.g., a magnetic floppy disk drive (“FDD”) 1216, a memory stick orflash drive reader, a memory card reader, etc.) and an optical diskdrive 1220 (e.g., which can read or write from a CD-ROM disc, a DVD, aBD, etc.). While the internal HDD 1214 is illustrated as located withinthe computer 1202, the internal HDD 1214 can also be configured forexternal use in a suitable chassis (not shown). Additionally, while notshown in environment 1200, a solid state drive (“SSD”) could be used inaddition to, or in place of, an HDD 1214. The HDD 1214, external storagedevice(s) 1216 and optical disk drive 1220 can be connected to thesystem bus 1208 by an HDD interface 1224, an external storage interface1226 and an optical drive interface 1228, respectively. The interface1224 for external drive implementations can include at least one or bothof Universal Serial Bus (“USB”) and Institute of Electrical andElectronics Engineers (“IEEE”) 1394 interface technologies. Otherexternal drive connection technologies are within contemplation of theembodiments described herein.

The drives and their associated computer-readable storage media providenonvolatile storage of data, data structures, computer-executableinstructions, and so forth. For the computer 1202, the drives andstorage media accommodate the storage of any data in a suitable digitalformat. Although the description of computer-readable storage mediaabove refers to respective types of storage devices, it should beappreciated by those skilled in the art that other types of storagemedia which are readable by a computer, whether presently existing ordeveloped in the future, could also be used in the example operatingenvironment, and further, that any such storage media can containcomputer-executable instructions for performing the methods describedherein.

A number of program modules can be stored in the drives and RAM 1212,including an operating system 1230, one or more application programs1232, other program modules 1234 and program data 1236. All or portionsof the operating system, applications, modules, and/or data can also becached in the RAM 1212. The systems and methods described herein can beimplemented utilizing various commercially available operating systemsor combinations of operating systems.

Computer 1202 can optionally comprise emulation technologies. Forexample, a hypervisor (not shown) or other intermediary can emulate ahardware environment for operating system 1230, and the emulatedhardware can optionally be different from the hardware illustrated inFIG. 12. In such an embodiment, operating system 1230 can comprise onevirtual machine (“VM”) of multiple VMs hosted at computer 1202.Furthermore, operating system 1230 can provide runtime environments,such as the Java runtime environment or the .NET framework, forapplications 1232. Runtime environments are consistent executionenvironments that allow applications 1232 to run on any operating systemthat includes the runtime environment. Similarly, operating system 1230can support containers, and applications 1232 can be in the form ofcontainers, which are lightweight, standalone, executable packages ofsoftware that include, e.g., code, runtime, system tools, systemlibraries and settings for an application.

Further, computer 1202 can be enable with a security module, such as atrusted processing module (“TPM”). For instance with a TPM, bootcomponents hash next in time boot components, and wait for a match ofresults to secured values, before loading a next boot component. Thisprocess can take place at any layer in the code execution stack ofcomputer 1202, e.g., applied at the application execution level or atthe operating system (“OS”) kernel level, thereby enabling security atany level of code execution.

A user can enter commands and information into the computer 1202 throughone or more wired/wireless input devices, e.g., a keyboard 1238, a touchscreen 1240, and a pointing device, such as a mouse 1242. Other inputdevices (not shown) can include a microphone, an infrared (“IR”) remotecontrol, a radio frequency (“RF”) remote control, or other remotecontrol, a joystick, a virtual reality controller and/or virtual realityheadset, a game pad, a stylus pen, an image input device, e.g.,camera(s), a gesture sensor input device, a vision movement sensor inputdevice, an emotion or facial detection device, a biometric input device,e.g., fingerprint or iris scanner, or the like. These and other inputdevices are often connected to the processing unit 1204 through an inputdevice interface 1244 that can be coupled to the system bus 1208, butcan be connected by other interfaces, such as a parallel port, an IEEE1394 serial port, a game port, a USB port, an IR interface, a BLUETOOTH®interface, etc.

A monitor 1246 or other type of display device can be also connected tothe system bus 1208 via an interface, such as a video adapter 1248. Inaddition to the monitor 1246, a computer typically includes otherperipheral output devices (not shown), such as speakers, printers, etc.

The computer 1202 can operate in a networked environment using logicalconnections via wired and/or wireless communications to one or moreremote computers, such as a remote computer(s) 1250. The remotecomputer(s) 1250 can be a workstation, a server computer, a router, apersonal computer, portable computer, microprocessor-based entertainmentappliance, a peer device or other common network node, and typicallyincludes many or all of the elements described relative to the computer1202, although, for purposes of brevity, only a memory/storage device1252 is illustrated. The logical connections depicted includewired/wireless connectivity to a local area network (“LAN”) 1254 and/orlarger networks, e.g., a wide area network (“WAN”) 1256. Such LAN andWAN networking environments are commonplace in offices and companies,and facilitate enterprise-wide computer networks, such as intranets, allof which can connect to a global communications network, e.g., theInternet.

When used in a LAN networking environment, the computer 1202 can beconnected to the local network 1254 through a wired and/or wirelesscommunication network interface or adapter 1258. The adapter 1258 canfacilitate wired or wireless communication to the LAN 1254, which canalso include a wireless access point (“AP”) disposed thereon forcommunicating with the adapter 1258 in a wireless mode.

When used in a WAN networking environment, the computer 1202 can includea modem 1260 or can be connected to a communications server on the WAN1256 via other means for establishing communications over the WAN 1256,such as by way of the Internet. The modem 1260, which can be internal orexternal and a wired or wireless device, can be connected to the systembus 1208 via the input device interface 1244. In a networkedenvironment, program modules depicted relative to the computer 1202 orportions thereof, can be stored in the remote memory/storage device1252. It will be appreciated that the network connections shown areexample and other means of establishing a communications link betweenthe computers can be used.

When used in either a LAN or WAN networking environment, the computer1202 can access cloud storage systems or other network-based storagesystems in addition to, or in place of, external storage devices 1216 asdescribed above. Generally, a connection between the computer 1202 and acloud storage system can be established over a LAN 1254 or WAN 1256e.g., by the adapter 1258 or modem 1260, respectively. Upon connectingthe computer 1202 to an associated cloud storage system, the externalstorage interface 1226 can, with the aid of the adapter 1258 and/ormodem 1260, manage storage provided by the cloud storage system as itwould other types of external storage. For instance, the externalstorage interface 1226 can be configured to provide access to cloudstorage sources as if those sources were physically connected to thecomputer 1202.

The computer 1202 can be operable to communicate with any wirelessdevices or entities operatively disposed in wireless communication,e.g., a printer, scanner, desktop and/or portable computer, portabledata assistant, communications satellite, any piece of equipment orlocation associated with a wirelessly detectable tag (e.g., a kiosk,news stand, store shelf, etc.), and telephone. This can include WirelessFidelity (“Wi-Fi”) and BLUETOOTH® wireless technologies. Thus, thecommunication can be a predefined structure as with a conventionalnetwork or simply an ad hoc communication between at least two devices.

What has been described above include mere examples of systems, computerprogram products and computer-implemented methods. It is, of course, notpossible to describe every conceivable combination of components,products and/or computer-implemented methods for purposes of describingthis disclosure, but one of ordinary skill in the art can recognize thatmany further combinations and permutations of this disclosure arepossible. Furthermore, to the extent that the terms “includes,” “has,”“possesses,” and the like are used in the detailed description, claims,appendices and drawings such terms are intended to be inclusive in amanner similar to the term “comprising” as “comprising” is interpretedwhen employed as a transitional word in a claim. The descriptions of thevarious embodiments have been presented for purposes of illustration,but are not intended to be exhaustive or limited to the embodimentsdisclosed. Many modifications and variations will be apparent to thoseof ordinary skill in the art without departing from the scope and spiritof the described embodiments. The terminology used herein was chosen tobest explain the principles of the embodiments, the practicalapplication or technical improvement over technologies found in themarketplace, or to enable others of ordinary skill in the art tounderstand the embodiments disclosed herein.

What is claimed is:
 1. A system, comprising: a memory that storescomputer executable components; and a processor, operably coupled to thememory, and that executes the computer executable components stored inthe memory, wherein the computer executable components comprise: a resetcomponent that de-excites a qubit system to a target state bytransitioning a population of a first excited state of the qubit systemto a ground state and by applying a signal to the qubit system thattransitions a population of a second excited state to the first excitedstate.
 2. The system of claim 1, further comprising: a ground statecomponent that transitions the population of the first excited state tothe ground state by a reset selected from the group consisting of ameasurement based reset, a sideband based reset, and a low-Q reset. 3.The system of claim 2, wherein the reset is the low-Q reset, and whereinthe ground state component further renders a low-Q resonator of thequbit system to degenerate with the first excited state.
 4. The systemof claim 2, further comprising: a transition component that generatesthe signal that transitions the population of the second excited stateto the first excited state, wherein the signal comprises at least onetransition signal selected from the group consisting of a pi pulsetransition signal and a microwave chirp transmission signal.
 5. Thesystem of claim 4, wherein the at least one transition signal removes aphoton from a qubit at the second excited state to de-excite the qubitto the first excited state.
 6. The system of claim 4, wherein the firstexcited state and the second excited state are comprised within aplurality of excited states, and wherein the at least one transitionsignal removes a photon from the plurality of excited states.
 7. Thesystem of claim 4, wherein the at least one transition signal is aseries of the pi pulse transition signals, wherein the transitioncomponent generates a first pi pulse transition signal of the seriesthat de-excites a population of a third excited state of the qubitsystem to the second excited state, and wherein the signal is a secondpi pulse transition signal of the series.
 8. A computer-implementedmethod, comprising: transitioning, by a system operatively coupled to aprocessor, a population of a first excited state of a qubit system to aground state; and applying, by the system, a signal to the qubit systemthat transitions a population of a second excited state to the firstexcited state.
 9. The computer-implemented method of claim 8, whereinthe transitioning the population of the first excited state to theground state is performed via a reset selected from the group consistingof a measurement based reset, a sideband based reset, and a low-Q reset.10. The computer-implemented method of claim 9, wherein the reset is thelow-Q reset, and wherein the computer-implemented method furthercomprises: rendering, by the system, a low-Q resonator of the qubitsystem to degenerate with the first excited state.
 11. Thecomputer-implemented method of claim 8, further comprising: generating,by the system, the signal that transitions the population of the secondexcited state to the first excited state, wherein the signal comprisesat least one transition signal selected from the group consisting of api pulse transition signal and a microwave chirp transmission signal.12. The computer-implemented method of claim 11, wherein the at leastone transition signal removes a photon from a qubit at the secondexcited state to de-excite the qubit to the first excited state.
 13. Thecomputer-implemented method of claim 11, wherein the first excited stateand the second excited state are comprised within a plurality of excitedstates, and wherein the at least one transition signal removes a photonfrom the plurality of excited states.
 14. The computer-implementedmethod of claim 11, wherein the at least one transition signal is aseries of the pi pulse transition signals, wherein thecomputer-implemented method further comprises generating, by the system,a first pi pulse transition signal of the series that de-excites apopulation of a third excited state of the qubit system to the secondexcited state, and wherein the signal is a second pi pulse transitionsignal of the series.
 15. A computer program product for de-exciting aqubit system, the computer program product comprising a computerreadable storage medium having program instructions embodied therewith,the program instructions executable by a processor to cause theprocessor to: transition, by the processor, a population of a firstexcited state of the qubit system to a ground state; and apply, by theprocessor, a signal to the qubit system that transitions a population ofa second excited state to the first excited state.
 16. The computerprogram product of claim 15, wherein the program instructions furthercause the processor to transition the population of the first excitedstate to the ground state via a reset selected from the group consistingof a measurement based reset, a sideband based reset, and a low-Q reset.17. The computer program product of claim 16, wherein the reset is thelow-Q reset, and wherein the program instructions further cause theprocessor to: render, by the processor, a low-Q resonator of the qubitsystem to degenerate with the first excited state.
 18. The computerprogram product of claim 15, wherein the program instructions furthercause the processor to: generate, by the processor, the signal thattransitions the population of the second excited state to the firstexcited state, wherein the signal comprises at least one transitionsignal selected from the group consisting of a pi pulse transitionsignal and a microwave chirp transmission signal.
 19. The computerprogram product of claim 18, wherein the at least one transition signalremoves a photon from a qubit at the second excited state to de-excitethe qubit to the first excited state.
 20. The computer program productof claim 18, wherein the first excited state and the second excitedstate are comprised within a plurality of excited states, and whereinthe at least one transition signal removes a photon from the pluralityof excited states.